[JNI] Add setKernelPinnedCopyThreshold and setPinnedAllocationThresho…

…ld (#16288)

In 24.08 two new cuDF methods are being added, and the second method is still in flight (see: #16206):

```
cudf::set_kernel_pinned_copy_threshold
cudf::set_allocate_host_as_pinned_threshold
```

We'd like to expose these methods in our JNI layer. I created a Cudf.java with the two static methods, and put the definitions in CudfJni.cpp. 

Marked as draft since I need #16206 to merge, and we are still testing it.

Authors:
  - Alessandro Bellina (https://github.com/abellina)
  - Nghia Truong (https://github.com/ttnghia)

Approvers:
  - Robert (Bobby) Evans (https://github.com/revans2)
  - Jason Lowe (https://github.com/jlowe)

URL: #16288

java/src/main/java/ai/rapids/cudf/Cudf.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2024, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ai.rapids.cudf;
+
+public class Cudf {
+
+  static {
+    NativeDepsLoader.loadNativeDeps();
+  }
+
+  /**
+   * cuDF copies that are smaller than the threshold will use a kernel to copy, instead
+   * of cudaMemcpyAsync.
+   */
+  public static native void setKernelPinnedCopyThreshold(long kernelPinnedCopyThreshold);
+
+  /**
+   * cudf allocations that are smaller than the threshold will use the pinned host
+   * memory resource.
+   */
+  public static native void setPinnedAllocationThreshold(long pinnedAllocationThreshold);
+}

java/src/main/native/src/CudfJni.cpp

@@ -18,6 +18,7 @@
 
 #include <cudf/copying.hpp>
 #include <cudf/utilities/default_stream.hpp>
+#include <cudf/utilities/pinned_memory.hpp>
 
 #include <sstream>
 
@@ -201,4 +202,28 @@ JNIEXPORT jboolean JNICALL Java_ai_rapids_cudf_Cuda_isPtdsEnabled(JNIEnv* env, j
   return cudf::jni::is_ptds_enabled;
 }
 
+JNIEXPORT void JNICALL Java_ai_rapids_cudf_Cudf_setKernelPinnedCopyThreshold(JNIEnv* env,
+                                                                             jclass clazz,
+                                                                             jlong jthreshold)
+{
+  try {
+    cudf::jni::auto_set_device(env);
+    auto threshold = static_cast<std::size_t>(jthreshold);
+    cudf::set_kernel_pinned_copy_threshold(threshold);
+  }
+  CATCH_STD(env, )
+}
+
+JNIEXPORT void JNICALL Java_ai_rapids_cudf_Cudf_setPinnedAllocationThreshold(JNIEnv* env,
+                                                                             jclass clazz,
+                                                                             jlong jthreshold)
+{
+  try {
+    cudf::jni::auto_set_device(env);
+    auto threshold = static_cast<std::size_t>(jthreshold);
+    cudf::set_allocate_host_as_pinned_threshold(threshold);
+  }
+  CATCH_STD(env, )
+}
+
 }  // extern "C"